Anthocyanin inhibits high glucose-induced hepatic mtGPAT1 activation and prevents fatty acid synthesis through PKCζ

Mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 (mtGPAT1) controls the first step of triacylglycerol (TAG) synthesis and is critical to the understanding of chronic metabolic disorders such as primary nonalcoholic fatty liver disease (NAFLD). Anthocyanin, a large group of polyphenols, was negatively correlated with hepatic lipid accumulation, but its impact on mtGPAT1 activity and NAFLD has yet to be determined. Hepatoma cell lines and KKAy mice were used to investigate the impact of anthocyanin on high glucose-induced mtGPAT1 activation and hepatic steatosis. Treatment with anthocyanin cyanidin-3-O-β-glucoside (Cy-3-g) reduced high glucose-induced GPAT1 activity through the prevention of mtGPAT1 translocation from the endoplasmic reticulum to the outer mitochondrial membrane (OMM), thereby suppressing intracellular de novo lipid synthesis. Cy-3-g treatment also increased protein kinase C ζ phosphorylation and membrane translocation in order to phosphorylate the mtF0F1-ATPase β-subunit, reducing its enzymatic activity and thus inhibiting mtGPAT1 activation. In vivo studies further showed that Cy-3-g treatment significantly decreases hepatic mtGPAT1 activity and its presence in OMM isolated from livers, thus ameliorating hepatic steatosis in diabetic KKAy mice. Our findings reveal a novel mechanism by which anthocyanin regulates lipogenesis and thereby inhibits hepatic steatosis, suggesting its potential therapeutic application in diabetes and related steatotic liver diseases. Mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 (mtGPAT1) controls the first step of triacylglycerol (TAG) synthesis and is critical to the understanding of chronic metabolic disorders such as primary nonalcoholic fatty liver disease (NAFLD). Anthocyanin, a large group of polyphenols, was negatively correlated with hepatic lipid accumulation, but its impact on mtGPAT1 activity and NAFLD has yet to be determined. Hepatoma cell lines and KKAy mice were used to investigate the impact of anthocyanin on high glucose-induced mtGPAT1 activation and hepatic steatosis. Treatment with anthocyanin cyanidin-3-O-β-glucoside (Cy-3-g) reduced high glucose-induced GPAT1 activity through the prevention of mtGPAT1 translocation from the endoplasmic reticulum to the outer mitochondrial membrane (OMM), thereby suppressing intracellular de novo lipid synthesis. Cy-3-g treatment also increased protein kinase C ζ phosphorylation and membrane translocation in order to phosphorylate the mtF0F1-ATPase β-subunit, reducing its enzymatic activity and thus inhibiting mtGPAT1 activation. In vivo studies further showed that Cy-3-g treatment significantly decreases hepatic mtGPAT1 activity and its presence in OMM isolated from livers, thus ameliorating hepatic steatosis in diabetic KKAy mice. Our findings reveal a novel mechanism by which anthocyanin regulates lipogenesis and thereby inhibits hepatic steatosis, suggesting its potential therapeutic application in diabetes and related steatotic liver diseases. Nonalcoholic fatty liver disease (NAFLD) is considered to be the most common hepatic manifestation of metabolic syndromes such as diabetes and obesity (1Flegal K.M. Carroll M.D. Ogden C.L. Curtin L.R. Prevalence and trends in obesity among US adults.JAMA. 2010; 303: 235-241Crossref PubMed Scopus (5355) Google Scholar). The dysregulation of triacylglycerol (TAG) metabolism may contribute to the derangement of hepatic lipid homeostasis and chronic liver damage (2Gaemers I.C. Groen A.K. New insights in the pathogenesis of non-alcoholic fatty liver disease.Curr. Opin. Lipidol. 2006; 17: 268-273Crossref PubMed Scopus (44) Google Scholar). Thus, understanding the steps involved in the regulation of hepatic TAG synthesis would likely provide potential new targets for the treatment and prevention of this condition. Glycerol-sn-3-phosphate acyltransferase (GPAT) controls the rate-limiting step in the glycerol 3-phosphate pathway, converting glycerol-3-phosphate and acyl-CoA into phosphatidic acid, which is the precursor of TAG and glycerophospholipids (3Coleman R.A. Lee D.P. Enzymes of triacylglycerol synthesis and their regulation.Prog. Lipid Res. 2004; 43: 134-176Crossref PubMed Scopus (723) Google Scholar). Currently, two GPAT activities exist in most mammalian cells and tissues, the first of which (msGPAT) is located in the endoplasmic reticulum (ER) and the second of which is located in the mitochondria, which is associated with the outer mitochondrial membrane (OMM) (4Lewin T.M. Schwerbrock N.M. Lee D.P. Coleman R.A. Identification of a new glycerol-3-phosphate acyltransferase isoenzyme, mtGPAT2, in mitochondria.J. Biol. Chem. 2004; 279: 13488-13495Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 5Dircks L.K. Mammalian mitochondrial glycerol-3-phosphate acyltransferase.Biochim. Biophys. Acta. 1997; 1348: 17-26Crossref PubMed Scopus (60) Google Scholar). The activities of mtGPAT and microsomal GPAT can be differentiated by their selective sensitivity to sulfhydryl group reactive reagents such as N-ethylmaleimide (NEM) (6Sul H.S. Wang D. Nutritional and hormonal regulation of enzymes in fat synthesis: studies of fatty acid synthase and mitochondrial glycerol-3-phosphate acyltransferase gene transcription.Annu. Rev. Nutr. 1998; 18: 331-351Crossref PubMed Scopus (236) Google Scholar). Previous in vitro studies have demonstrated that the overexpression of mtGPAT primarily results in the trafficking of exogenous fatty acids into the TAG pool rather than the incorporation of these acids into phospholipid fractions or into oxidative degradation (7Lindén D. William-Olsson L. Rhedin M. Asztély A.K. Clapham J.C. Schreyer S. Overexpression of mitochondrial GPAT in rat hepatocytes leads to decreased fatty acid oxidation and increased glycerolipid biosynthesis.J. Lipid Res. 2004; 45: 1279-1288Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar). Thus, it has been proposed that the mtGPAT1 isoform might serve as a valve that channels fatty-acid derivatives preferentially toward glycerolipid synthesis, counteracting their partitioning into the β-oxidation pathway. On the contrary, deletion of mtGPAT in mice substantially limits the incorporation of acyl-CoA species into the sn-glycerol 3-phosphate pathway in liver, resulting in markedly lower levels of hepatic lipid synthesis and the prevention of hepatic steatosis (8Neschen S. Morino K. Hammond L.E. Zhang D. Liu Z.X. Romanelli A.J. Cline G.W. Pongratz R.L. Zhang X.M. Choi C.S. Prevention of hepatic steatosis and hepatic insulin resistance in mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 knockout mice.Cell Metab. 2005; 2: 55-65Abstract Full Text Full Text PDF PubMed Scopus (217) Google Scholar, 9Wendel A.A. Li L.O. Li Y. Cline G.W. Shulman G.I. Coleman R.A. Glycerol-3-phosphate acyltransferase 1 deficiency in ob/ob mice diminishes hepatic steatosis but does not protect against insulin resistance or obesity.Diabetes. 2010; 59: 1321-1329Crossref PubMed Scopus (46) Google Scholar). Because the liver is among the organs displaying the highest specific mtGPAT enzyme activity, mtGPAT1 was regarded as a novel and potential target for the treatment of hepatic steatosis. Anthocyanins are naturally occurring pigments in the plant kingdom and are therefore widely distributed as plant polyphenols. Recently, anthocyanins have received more attention as potential agents to halt, reverse, and improve the symptoms of many degenerative diseases (10Williams C.A. Grayer R.J. Anthocyanins and other flavonoids.Nat. Prod. Rep. 2004; 21: 539-573Crossref PubMed Scopus (388) Google Scholar, 11Kong J.M. Chia L.S. Goh N.K. Chia T.F. Brouillard R. Analysis and biological activities of anthocyanins.Phytochemistry. 2003; 64: 923-933Crossref PubMed Scopus (1272) Google Scholar, 12Xia M. Ling W.H. Ma J. Kitts D.D. Zawistowski J. Supplementation of diets with the black rice pigment fraction attenuates atherosclerotic plaque formation in apolipoprotein e deficient mice.J. Nutr. 2003; 133: 744-751Crossref PubMed Scopus (126) Google Scholar, 13Xia X. Ling W. Ma J. Xia M. Hou M. Wang Q. Zhu H. Tang Z. An anthocyanin-rich extract from black rice enhances atherosclerotic plaque stabilization in apolipoprotein E-deficient mice.J. Nutr. 2006; 136: 2220-2225Crossref PubMed Scopus (205) Google Scholar). Recent studies have demonstrated that anthocyanin-rich foods improve hyperlipidemia and significantly ameliorate hepatic steatosis (14Seymour E.M. Singer A.A. Kirakosyan A. Urcuyo-Llanes D.E. Kaufman P.B. Bolling S.F. Altered hyperlipidemia, hepatic steatosis, and hepatic peroxisome proliferator-activated receptors in rats with intake of tart cherry.J. Med. Food. 2008; 11: 252-259Crossref PubMed Scopus (132) Google Scholar) but the underlying molecular mechanism is incomplete. Because GPAT1 is a major lipogenic enzyme implicated in the development of hepatic steatosis, we currently evaluated the effects of anthocyanin on high glucose-induced mtGPAT1 activation in vitro and in vivo and its impact on hepatic steatosis. Notably, we demonstrated that anthocyanin in hepatocytes abolishes high glucose-induced mtGPAT1 activation through a mechanism involving PKCζ activation and thus ameliorates hepatic steatosis in obese diabetic KKAy mice. HepG2 cells (human hepatoma cell line, ATCC #HB 8065, Manassas, VA) were cultured in DMEM (Gibco, Carlsbad, CA) supplemented with 10% FBS and antibiotics in a PKCζ activation HepG2 cells were a of for to were by the with to of PKCζ and for a of of were in DMEM for to and were of PKCζ targets it to the resulting in a kinase activity was to than that of PKCζ A. A. J. kinase is by protein kinase and in a Biol. PubMed Google Scholar). An was by and as M. J. K. protein trafficking to insulin in PubMed Scopus Google Scholar). The was into the CA) the and and into were and with the of the were of the and of were in of for for cell were in 1 1 and and protein were the and membrane fractions were as K. J. R. H. New application of a to and for the of acid in cell of and Chem. 2005; PubMed Scopus Google Scholar). Mitochondrial fractions from the hepatocytes and of mice were as K. J. R. H. New application of a to and for the of acid in cell of and Chem. 2005; PubMed Scopus Google Scholar) and in or as J. of mitochondrial synthase by J. PubMed Scopus Google Scholar). of from cell membrane or liver were by and to The were with primary against and PKCζ GPAT1 mitochondrial and The were with and with the is a pool of to the gene to the PKCζ gene was of with pool that does not target was used as a The cells were with these HepG2 cells or of a liver was a in 1 1 and and were by for was to and for to the The was with the for protein and enzymatic to of mtGPAT1 activity, the mitochondrial was on for in the presence of to other GPAT The mtGPAT activities were of protein for 1 in and 1 and 1 The was by of to extract the acid was by in a for The was to and further was two with The was to a and for (7Lindén D. William-Olsson L. Rhedin M. Asztély A.K. Clapham J.C. Schreyer S. Overexpression of mitochondrial GPAT in rat hepatocytes leads to decreased fatty acid oxidation and increased glycerolipid biosynthesis.J. Lipid Res. 2004; 45: 1279-1288Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar, J. and of protein from rat protein a of mitochondrial Biol. PubMed Scopus Google Scholar). The of sensitivity on a has been demonstrated to mitochondrial from GPAT activity R.A. Wang S. M. Coleman R.A. Mitochondrial glycerol acyltransferase the incorporation of exogenous fatty acids into Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). Mitochondrial activity was by the of to the oxidation of the kinase and activity in was in the presence of the enzyme or the effects of anthocyanin on the other enzymes used in the with kinase and was from the and the was by the of K. kinase regulates triacylglycerol synthesis and fatty acid oxidation in liver and that acyltransferase is a novel J. PubMed Scopus Google Scholar). The of the HepG2 cells was with The can be for and is The HepG2 cells were with Cy-3-g for in The cells were with for the cells with and with 1 was with a Lee C.S. Lee Lee S. activity of for 2006; PubMed Scopus Google Scholar). were with acid as were with and from the were from or in and the into was by and and (7Lindén D. William-Olsson L. Rhedin M. Asztély A.K. Clapham J.C. Schreyer S. Overexpression of mitochondrial GPAT in rat hepatocytes leads to decreased fatty acid oxidation and increased glycerolipid biosynthesis.J. Lipid Res. 2004; 45: 1279-1288Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar). was in and were into and in 1 of fraction of the lipid extract was and in for 1 The was reagents C.A. An J. M. overexpression of acyltransferase 1 in rats insulin Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The of hepatic in HepG2 cells was by the of hepatic from cell and the enzymatic of the H.S. Wang X. A. of in mice results in fatty liver formation to and Metab. 2010; Full Text Full Text PDF PubMed Scopus Google Scholar). were in and were and in were in and were X. X. Y. J. Y. Wang X. Zhu Y. Wang proliferator-activated and hepatic lipogenesis in obese diabetic 2008; PubMed Scopus Google Scholar). PKCζ kinase activity was PKCζ KKAy mice of were from the The mice were on a or on Cy-3-g for Cy-3-g was to the of these was to and was from to the of Cy-3-g and was in the and was in for more than 1 the critical of mice also received PKCζ The PKCζ was by were in and controls received of the used a as demonstrated A. K. M. overexpression of microsomal protein results in increased in vivo of and apolipoprotein Lipid Res. Full Text Full Text PDF PubMed Google Scholar). mice were with of 10% which inhibits and therefore the of from the by and was to 1 was and for were as with their liver were as was by were used to in to with by the of was considered first the effects of anthocyanin GPAT1 protein HepG2 cells were with and high of or in the presence of anthocyanin Cy-3-g for GPAT1 protein was in the fractions the cells were cultured in a the presence of high levels a in GPAT1 protein in the and in the that a high of GPAT1 translocation in HepG2 this translocation of GPAT1 to the OMM was by anthocyanin Cy-3-g in a effects were not to the of GPAT1 the of GPAT1 was not by The of fractions was with the specific the presence of and the of in and the presence of and the of in OMM that GPAT1 is more in OMM M. Coleman R.A. Mitochondrial acyltransferase 1 is most in outer mitochondrial membrane but not in mitochondrial associated Biophys. Acta. PubMed Scopus Google Scholar). thus evaluated the impact of GPAT1 translocation by anthocyanin its enzymatic activity in HepG2 with of high treatment a in GPAT activity and mtGPAT1 activity of which were by Cy-3-g in a GPAT1 activity was treatment by Cy-3-g further the of mtGPAT1 activity by anthocyanin is of we de novo lipid with high levels showed a in intracellular TAG synthesis which was markedly by anthocyanin Cy-3-g treatment not the of into hepatocytes Cy-3-g markedly intracellular lipid as by the and Mitochondrial synthase is a mitochondrial enzyme of two and The molecular Rev. 1997; PubMed Scopus Google Scholar). the of in high glucose-induced mtGPAT1 activation. a specific of the the of translocation in and a specific of the of the mitochondrial the high glucose-induced GPAT1 translocation and activity is of with the located the of mitochondrial with to for the mechanism of Full Text Full Text PDF PubMed Scopus Google Scholar). HepG2 cells with a specific against the to further the of on GPAT1 Notably, we that the high activation of GPAT1 translocation from the to the OMM and in mtGPAT1 activity On the contrary, overexpression of the the high glucose-induced GPAT1 translocation and mtGPAT1 activity that the of is for high mtGPAT1 activation. further the activity of high in the of the activity and the The a of mitochondrial that with the to the activity of by the Biol. Chem. Full Text Full Text PDF PubMed Scopus Google the and the high activity Because activity is a of a on the membrane of is a that as and can be by high by synthase the cell the activity of mtGPAT1 by to the by high levels The of agents was not suggesting that a mtGPAT1 activation pathway. a in mtGPAT1 activation. In which and the and the high mtGPAT1 activation a of showed a of mtGPAT1 activation. a of these that may be a specific pathway for mtGPAT1 activation. the effects of anthocyanin mtGPAT1 activity were on the of Cy-3-g treatment was to activity in a further showed that the of Cy-3-g was but was for and that anthocyanin Cy-3-g is a of not have other kinase and which were used in the activity PKCζ is isoform of the and has been implicated as a potential target for and D. kinase C and the regulation of cell J. 279: PubMed Google Scholar, S. S. M. The critical of protein kinase C in hepatic and in Lipid Res. Full Text Full Text PDF PubMed Scopus Google Scholar). the of PKCζ activation in the of we HepG2 cells to or two Notably, in the presence of or the in mtF0F1-ATPase activity by anthocyanin was markedly that activation is involved in the effects of this to the isoform specific T.M. Lee H. Y. R.A. is the primary of by PubMed Scopus Google Scholar). The of high mtF0F1-ATPase by anthocyanin was significantly by a PKCζ but not by a or by the further the critical of we specific PKCζ and that of HepG2 cells with this also significantly and reduced of high glucose-induced mtF0F1-ATPase activation this was by the PKCζ the effects of anthocyanin GPAT1 translocation and intracellular lipid in HepG2 cells Because the phosphorylation of a critical in the activation of is the first step of activation Z. Y. R. D. of by protein kinase is for activation of the protein kinase in 2008; PubMed Scopus Google we the impact of anthocyanin on PKCζ activation in HepG2 The levels of PKCζ were to be in HepG2 cells high In anthocyanin treatment significantly the PKCζ phosphorylation levels The translocation of PKCζ is considered a critical step in PKCζ and the of HepG2 cells to anthocyanin significantly increased the levels of PKCζ in membrane fractions but these levels in the The of these fractions was by with against specific protein of the and membrane lower A. A. J. kinase is by protein kinase and in a Biol. PubMed Google Scholar). In anthocyanin significantly increased the specific PKCζ kinase activity in HepG2 cells has been demonstrated to be involved in the of other through the phosphorylation of and acid on these of protein kinase C and its impact on diabetic Res. 2010; PubMed Scopus Google Scholar). have acid X. kinase inhibits the of oxidative phosphorylation in J. 2004; PubMed Scopus Google and we further the which is by that anthocyanin treatment in the increased phosphorylation of the β-subunit, which was by PKCζ further to PKCζ the phosphorylation of the and PKCζ increased phosphorylation in the the of phosphorylation in and high HepG2 cells 1 and resulting in the of levels impact was not further by anthocyanin Cy-3-g that PKCζ the phosphorylation and degradation of the of investigate the of the phosphorylation of the of by we in vitro to this the enzyme The activity of by high levels was decreased by in the presence of PKCζ to activity of HepG2 cells with PKCζ also the translocation of GPAT1 from the to OMM results that phosphorylation by PKCζ has the effects of anthocyanin on mtGPAT1 activity and hepatic steatosis in obese diabetic KKAy mice were or supplemented with anthocyanin Cy-3-g the GPAT1 protein was to in the fractions from the isolated from mice but was in the in the of KKAy that to high levels may the translocation of this this translocation was in the of KKAy mice supplemented with anthocyanin In the mtGPAT1 activity was increased in mitochondrial fractions from the of KKAy mice mice. In anthocyanin significantly decreased this mtGPAT1 activity findings that anthocyanin mtGPAT1 translocation from the to the mitochondria, it is anthocyanin treatment also phosphorylation levels and enzymatic activity in KKAy mice. anthocyanin not the but significantly reduced levels evaluated PKCζ phosphorylation and its kinase activity in KKAy mice. treatment increased the levels of which is for the activity of this anthocyanin a of PKCζ activity with KKAy mice In and showed that the from KKAy mice more lipid than of the mice. of KKAy mice reduced the of lipid and in the liver, of hepatic steatosis. steatosis also from a in this activity was with and were in the was in and suggesting that the from the liver was not in the presence of anthocyanin that the decreased hepatic by anthocyanin may be by the of synthesis rather than further the critical of PKCζ in the of hepatic steatosis by anthocyanin Cy-3-g in we a of the PKCζ by of PKCζ or PKCζ the effects of anthocyanin on GPAT1 translocation activity and lipid in The major findings of are that anthocyanin Cy-3-g PKCζ activation in HepG2 cells by its phosphorylation and its membrane The activation of PKCζ the of its activity, and inhibits mtGPAT1 to the of de novo lipid by high in vivo studies showed that of Cy-3-g increased PKCζ activity and decreased mtGPAT1 activity in the liver, thereby ameliorating the hepatic steatosis in diabetic KKAy mice. The novel mechanism we have is in which anthocyanin regulates hepatic lipid metabolism through the pathway. The of anthocyanin to mtGPAT1 activation and improve hepatic lipid metabolism also that it might be a in Anthocyanins are widely in the through the of foods (10Williams C.A. Grayer R.J. Anthocyanins and other flavonoids.Nat. Prod. Rep. 2004; 21: 539-573Crossref PubMed Scopus (388) Google Scholar, 11Kong J.M. Chia L.S. Goh N.K. Chia T.F. Brouillard R. Analysis and biological activities of anthocyanins.Phytochemistry. 2003; 64: 923-933Crossref PubMed Scopus (1272) Google Scholar). have the of anthocyanins as that protect against oxidative and studies have further the of anthocyanin in lipid metabolism (10Williams C.A. Grayer R.J. Anthocyanins and other flavonoids.Nat. Prod. Rep. 2004; 21: 539-573Crossref PubMed Scopus (388) Google Scholar, 11Kong J.M. Chia L.S. Goh N.K. Chia T.F. Brouillard R. Analysis and biological activities of anthocyanins.Phytochemistry. 2003; 64: 923-933Crossref PubMed Scopus (1272) Google Scholar, 12Xia M. Ling W.H. Ma J. Kitts D.D. Zawistowski J. Supplementation of diets with the black rice pigment fraction attenuates atherosclerotic plaque formation in apolipoprotein e deficient mice.J. Nutr. 2003; 133: 744-751Crossref PubMed Scopus (126) Google Scholar, M. Hou M. Zhu H. Ma J. Tang Z. Wang Q. Li Y. D. X. Anthocyanins from the of the peroxisome Biol. Chem. 2005; Full Text Full Text PDF PubMed Scopus (126) Google Scholar). the mtGPAT1 is to be in lipid homeostasis and as yet mtGPAT1 to the effects of In this we demonstrated that anthocyanin treatment inhibits mtGPAT1 activation in to high levels by GPAT1 translocation from the to the in resulting in a of mtGPAT1 activity and the lipogenic synthase as the of the cell by in the of and regulation of of most Biol. Chem. Full Text PDF PubMed Google Scholar). can also in the by and Our that of abolishes GPAT1 incorporation into the treatment mitochondrial GPAT activity, but a does not this suggesting that the may as in regulation of GPAT1 which can be by high Thus, we a novel that mtF0F1-ATPase the high glucose-induced activation of GPAT1 by the of GPAT1 from the to the OMM in In with the that synthase is a target for J. of mitochondrial synthase by J. PubMed Scopus Google we currently demonstrated that anthocyanin Cy-3-g treatment also significantly the activity and the Thus, the of anthocyanin with these enzymes be the mechanism underlying the of these a the of and to increased leads to a in the to the activation of protein kinase a decreases lipid synthesis in liver C.L. hepatic lipid through in HepG2 Lipid Res. Full Text Full Text PDF PubMed Scopus Google Scholar, J.M. R. S. Y. M. of lipid synthesis through activation of mechanism for the effects of Lipid Res. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). Thus, not the of and in effects of protein kinase C insulin effects on in and and lipid synthesis in liver and other metabolic of protein kinase and as by J. Metab. 2010; PubMed Scopus Google Scholar). activation of and to the development of hepatic hyperlipidemia, and insulin hepatic is considered as a potential target for S. S. M. The critical of protein kinase C in hepatic and in Lipid Res. Full Text Full Text PDF PubMed Scopus Google Scholar). PKCζ is a protein kinase that to the of J. M. kinase C the of Opin. Biol. 21: PubMed Scopus Google Scholar, S.F. of protein kinase C isoform Rev. 2008; PubMed Scopus Google it to lipid we the that PKCζ is primarily in the of mtGPAT1 activation and lipid synthesis by high levels in vitro and in or of PKCζ the impact of Cy-3-g mtGPAT1 activation in that PKCζ is primarily for the effects of of isoform of anthocyanin Cy-3-g treatment was to PKCζ and this is further by the results of PKCζ a that in enzymatic and activity, may of the for regulation of activity W. of is by in in PubMed Scopus Google Scholar). we have that exogenous of PKCζ in hepatocytes the phosphorylation the on and the of to the of the enzymatic activity of Thus, we provide into underlying the of findings that anthocyanin may through phosphorylation the further we KKAy a of diabetes with and nonalcoholic fatty liver S. M. M. Y. Y. M. M. oxidative in obesity and its impact on metabolic 2004; PubMed Scopus Google Scholar). In with Cy-3-g significantly lipid in and hepatic steatosis. is not likely to the effects of as Cy-3-g not the effects of Cy-3-g the fat of from KKAy mice by PKCζ and hepatic GPAT1 translocation and activity as in of PKCζ the effects of anthocyanin on hepatic mtGPAT1 activation and lipid results a mechanism by which PKCζ can studies are to the involved in PKCζ activation. it to be the effects are a of the anthocyanins or are specific to In for the first we a of PKCζ in inhibiting GPAT1 activation by anthocyanin the phosphorylation of the of a of these anthocyanin lipogenesis and ameliorates hepatic steatosis in hepatocytes and obese diabetic KKAy mice. Thus, findings provide the that PKCζ by anthocyanin may contribute to the prevention and treatment of steatotic liver associated with obesity and with protein kinase protein kinase C endoplasmic reticulum and mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 primary nonalcoholic fatty liver disease N-ethylmaleimide outer mitochondrial membrane protein kinase C ζ triacylglycerol